San Diego (/ˌsæn diˈeɪɡoʊ/ SAN dee-AY-goh, Spanish: [san ˈdjeɣo]; Spanish for 'Saint Didacus') is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States and the seat of San Diego County, the fifth most populous county in the United States, with 3,338,330 estimated residents as of 2019. The city is known for its mild year-round climate, natural deep-water harbor, extensive beaches and parks, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center. San Diego is the second largest city in the state of California, after Los Angeles.
Yulin, known as "Shangxun" in ancient times, began in the Spring and Autumn and warring States period, flourished in the Ming and Qing dynasties, and was stationed in Yansui Town (also known as Yulin Town), an important town on the nine frontiers of the Ming Dynasty. Emperor Kangxi engraved a stele of "two isolated cities and a thousand years of loyalty and courage". There is a good reputation of "the ancient city of Taichung in the north of South Tower, the sixth floor riding the street all over the world". Such a strange urban construction is rare in China, which is also an important symbol of Yulin as a national historical and cultural city. Yulin is located in the northernmost part of China's Shaanxi Province, at the junction of the Loess Plateau and Maowusu Sandy Land, which is the transitional area between the Loess Plateau and the Inner Mongolia Plateau. Facing the Yellow River and Shanxi Province in the east, Ningxia and Gansu in the west, Yan'an in the south and Ordos in the north, it is the border of Shaanxi, Gansu, Ningxia, Mongolia and Jin. It has jurisdiction over 2 districts, 1 county-level city and 9 counties, with a resident population of 340